The invention herein described relates generally to an electrical connector and fixture for a four-sided integrated circuit device.
For many years integrated circuits have been housed in dual-in-line packages (DIPs). A DIP has parallel rows of leads which extend from opposite sides of a body that houses an integrated circuit chip. The body of the DIP usually is rectangular and typically from 14 to 64 leads are spaced along the longer sides of the body on 0.100 inch (2.54 mm) centers. The DIP ordinarily is installed on a printed circuit board by soldering the leads to the circuit board or by inserting the leads into a DIP socket which has been soldered to the circuit board.
A number of test devices have been designed for testing DIPs. Examples of these devices are disclosed in the following U.S. patents:
______________________________________ No. Patentee ______________________________________ RE. 28,064 Venaleck et al 3,914,007 Seidler 4,012,097 Long et al ______________________________________
A number of fixtures or mounts also have been provided for DIPs and other electrical components, examples of which are shown in the following U.S. patents:
______________________________________ No. Patentee ______________________________________ 3,345,541 Cobaugh et al 3,968,433 Dobarganes 4,638,406 Samson ______________________________________
More recently, integrated circuit packages have been developed wherein leads are provided along four sides of a body that houses an integrated circuit chip or chips. Typically, the body or housing containing the integrated circuit is square and an equal number of leads are arranged along each side of the body. These integrated circuit devices are referred to as LCCs for leaded chip carriers. The leads usually are more closely spaced than the leads in a DIP device, and this coupled with the leads being located along all four sides of the LCC in part enables more denser packing of integrated circuits on printed circuit boards. Like a DIP, an LCC may be installed on a printed circuit board by soldering the leads thereof to the circuit board. However, the LCC ordinarily is surface mounted on the printed circuit board.
State-of-the-art LCCs, such as those known as quad flat pack carriers, or more simply quad packs, may have a large number such as 132 leads with 33 leads per side of the carrier body. The leads of these quad packs typically are quite delicate and are easily damaged and more easily displaced.
As with DIPs, it is desirable to have an electrical connector such as a test probe for making temporary electrical connections with each of the leads of an LCC for testing while the LCC is in place on a printed circuit board. Since the LCC has leads located along each of the four sides of the LCC body, test probes for DIPs cannot be used since they connect with leads on only two opposed sides of an integrated circuit package. Likewise, various fixtures or mounts provided for DIPs cannot be used with LCCs. In an effort to satisfy the need for a test probe for an LCC, a few electrical connector devices have been developed. Examples of these electrical connector devices are shown in the following U.S. patents:
______________________________________ No. Patentee ______________________________________ 4,541,676 Hansen et al 4,556,269 Anderson et al 4,671,590 Ignaziak 4,671,592 Ignaziak ______________________________________
These devices, in general, apply pressure to surface mounted leads of an LCC in a direction parallel to the printed circuit board. This does not present a problem with LCCs including J-shape, surface mount leads. However, a problem may arise if used with a quad pack surface mounted to a printed circuit board because the thin and fragile leads of the quad pack may not be able to withstand the pressure applied by the four-sided devices disclosed in these patents.
Accordingly, it would be desirable to provide an electrical connector for electrically connecting with an LCC or similar device wherein leads are arranged along four sides of the device. More particularly, it would be desirable to provide an electrical connector and related structure for enabling electrical connection to a surface mounted quad pack having a relatively large number of fragile leads.